2,098 research outputs found
Polynomial Profits in Renewable Resources Management
A system of renewal equations on a graph provides a framework to describe the
exploitation of a biological resource. In this context, we formulate an optimal
control problem, prove the existence of an optimal control and ensure that the
target cost function is polynomial in the control. In specific situations,
further information about the form of this dependence is obtained. As a
consequence, in some cases the optimal control is proved to be necessarily
bang--bang, in other cases the computations necessary to find the optimal
control are significantly reduced
Stability and Optimization in Structured Population Models on Graphs
We prove existence and uniqueness of solutions, continuous dependence from
the initial datum and stability with respect to the boundary condition in a
class of initial--boundary value problems for systems of balance laws. The
particular choice of the boundary condition allows to comprehend models with
very different structures. In particular, we consider a juvenile-adult model,
the problem of the optimal mating ratio and a model for the optimal management
of biological resources. The stability result obtained allows to tackle various
optimal management/control problems, providing sufficient conditions for the
existence of optimal choices/controls.Comment: 22 pages, 7 figure
The Conservation of Marcus Aurelius' Monument. Technical studies
The equestrian bronze monument of Marcus Aurelius in Rome has been further investigated, after restoration, mainly to foresee possible damages caused by outdoor exposure. At the same time a copy of it has been cast by following a new original method to obtain the intermediate model. New non-destructive tests have heen carried out to execute the above researches and in the end old and new methodologies can be consldered as a complex experimental tool to study and control outdoor bronze monument
Differential Equations Modeling Crowd Interactions
Nonlocal conservation laws are used to describe various realistic instances
of crowd behaviors. First, a basic analytic framework is established through an
"ad hoc" well posedness theorem for systems of nonlocal conservation laws in
several space dimensions interacting non locally with a system of ODEs.
Numerical integrations show possible applications to the interaction of
different groups of pedestrians, and also with other "agents".Comment: 26 pages, 5 figure
An economic evaluation of aripiprazole vs olanzapine adapted to the Italian setting using outcomes of metabolic syndrome and risk for diabetes in patients with schizophrenia
Giorgio L Colombo1, Mauro Caruggi2, Sergio Di Matteo1, Alessandro Rossi31S.A.V.E. Studi Analisi Valutazioni Economiche, Milano, Italy; 2Università degli Studi dell’Insubria, Varese, Italy; 3Università de L’Aquila, ItalyObjective: To evaluate the cost-effectiveness of aripiprazole and olanzapine in patients with schizophrenia.Methods: Data from a double-blind, randomized study demonstrating the efficacy of aripiprazole and olanzapine were used to observe new incidence of metabolic syndrome (26-week therapy) and to model the risk of developing diabetes over 5 years of therapy. Cumulative incidence of metabolic syndrome was compared using Kaplan–Meier estimates; diabetes risk was estimated using a validated, general population risk-prediction model. Economic assessment was conducted from the third-party payer perspective by evaluating pharmacotherapy costs of treating schizophrenia and medical costs associated with treating adverse metabolic effects in a hypothetical cohort of 1000 patients. Resource utilization and costs were derived from the underlying study and published data, using a 3% rate to discount costs and benefits.Results: For the patients switched from olanzapine to aripiprazole, treatment with aripiprazole was a dominant cost-saving strategy. Use of aripiprazole avoided 184 events of metabolic syndrome over 26 weeks of treatment, contributing to a real-world (RW) cost savings of €2.53 per patient and a total savings of approximately €465.52 over a 5-year period. For the same cohort, the risk-prediction model indicated that 34 occurrences of diabetes could be avoided over 5 years, corresponding to a RW cost savings of €56.86 per patient and a total saving of approximately €1,933.24. These savings reflect avoided costs in treating adverse metabolic events and comparable costs in the acquisition of aripiprazole.Conclusions: Maintenance aripiprazole therapy offers medical and economic benefits over olanzapine, reflected by reduced incidence of metabolic syndrome and diabetes and associated lower costs.Keywords: schizophrenia, cost-consequences, apripiprazole, olanzapine, metabolic syndrome, diabete
Self-apposing stent fracture in the context of myocardial bridging leading to in-stent chronic total occlusion: When the muscle trumps the metal
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